PubMed · 7236920
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M Marek, M Kubícek. 1981. Morphogen pattern formation and development in growth.. https://doi.org/10.1007/bf02462200
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In complex systems, responses to small perturbations are too diverse to definitely predict how much they would be, and then such diverse responses can be predicted in a probabilistic way. Here we study such a problem in scale-free networks, for example, the diameter changes by the deletion of a single vertex for various in silico and real-world scale-free networks. We find that the diameter changes are indeed diverse and their distribution exhibits an algebraic decay with an exponent zeta asymptotically. Interestingly, the exponent zeta is robust as zeta approximately 2.2(1) for most scale-free networks and insensitive to the degree exponents gamma as long as 2<gamma</=3. However, there is another type with zeta approximately 1.7(1) and its examples include the Internet and its related in silico model.
The skeletal dysplasias are a large, heterogeneous group of genetic conditions characterized by abnormal development, growth and maintenance of the elements (bones) that comprise the human skeleton. Many result in disproportionate short stature. The classification of these disorders has evolved over the past 30 years from purely clinical-pathological descriptions to a nosology that now also reflects their underlying molecular aetiology. Accurate diagnosis of these disorders requires comprehensive documentation of the history, analysis of longitudinal growth patterns, rigorous clinical evaluation of the individual and family, complete radiographic survey and, when available, examination of chondro-osseous specimens. The specific genetic defects underlying many of these conditions have now been elucidated, allowing links to be established between phenotype and genotype. Management revolves around treatment to prevent or minimize medical complications, psychosocial support of patients and their families, education of the medical profession and wider community and modification of the environment where appropriate.
A 43-yr-old male was referred because of an x-ray made after a fall, which showed open epiphysis of the arm. The man had always been short for his age; during childhood he once consulted a pediatrician because of short stature, but thereafter he never sought medical attention. At age 18 yr he was not allowed to join the army because of his height of 147 cm. He continued to grow steadily and finally reached 193 cm. He had no complaints and considered himself reasonably fit. Physical examination showed a disproportional man with a body mass index of 29.3 kg/m(2) and Tanner stage P1G1. Laboratory investigations showed hormone levels consistent with multiple pituitary deficiency, with dynamic tests consistent with hypothalamic or pituitary stalk disease. Magnetic resonance scanning of the brain showed a small anterior pituitary remnant, no pituitary stalk, and an ectopic neurohypophysis. This case of untreated panhypopituitarism shows a particular growth curve with an average growth velocity of 2 cm/yr, resembling patients with estrogen receptor mutation or aromatase deficiency. A literature study of other adult patients with untreated panhypopituitarism shows a variable growth pattern. Some speculations about possible reasons for this variability in clinical characteristics are presented.